Purchaser Order Locking Problem In PROXY interfaces

Hello Experts,

Scenario is as follows

landscape is : NON SAP system ->> PI --> ECC

Documents flowing is Purchaser order create and change

Problem is like when i receive same purchase order for change in few fraction of seconds and multiple time as i am already processing the same same PO the next interface goes into a error saying that the PO is locked by user so and so.

What could be possible solution for to avoid locking in first place .

Note its a asynchronous interface XML proxy message.

Thanks and Regards,

Anup Deshmukh

Still waiting for the inputs...!

PS : Moderators please move it to PI forum if it has to something with PI also